An apparatus for packaging pourable food in containers comprise a number of steps. In short, such an apparatus may comprise the steps of forming a tube of a web of packaging material, filling said tube with the pourable food, forming containers from the tube by transversally sealing and cutting the tube, and folding the containers to their final form. Further, the folding step can be divided into a number of sub-steps. For example, during a first folding sub-step performed in association to the sealing and cutting step, a section of the containers being sealed may be formed to have a rectangular cross-section. In later folding sub-steps, the container may be folded in such a way that a rectangular base is achieved, e.g. by folding the outer ends of the sealing end into the middle of the sealing end.
In order to reduce the risk of having leaking containers it is important that the folding is made correctly, since an improper folding can create tensions in the containers, which can result in leaking containers. This is especially important if the packaging material comprises several layers, such as a carton layer, plastic layers and an aluminum foil.
In order to facilitate the folding and thus reduce the risk of improper folding, packaging material having creasing lines may used. However, although packaging material provided with creasing lines is used, there is still a risk that the folding is made improperly.